As Many As

I might sound a complete fool on this but I do have had a couple of fallout on a particular phrase in GMAT questions which is 'As Many As'!!!

My spoken English has always been quite good for a non-native but this particular phrase has always squared me up.

Consider a problem

:

In a certain population, there are 3 times as many people aged 21 or under as there are people over 21. The ratio of those 21 or under to the total population is

A. 1 to 2
B. 1 to 3
C. 1 to 4
D. 2 to 3
E. 3 to 4

ALWAYS consider the later part as base and then move on:

Sol People aged > 21 = x

      People aged <= 21 = 3x

      Ration of <=21 and total = 3x : x + 3x

                                            = 3x : 4x 

                                            = 3 : 4 (E)